Unitary clamp assembly



Jan. 26, 1943 J. ROGQFF f 2,309,607

f 1 i l// 1 V INVENTOR. JUL 142v B56627 Patented Jan. 26, 1943 UNITABYCLAMP ASSEMBLY Julian Rogofi, New York, N. Y., assignor to BurndyEngineering Company, Inc., a. corporation of New York Application July30, 1940, Serial No. 348,346

1 Claim.

My invention relates to electrical connectors to join copper conductorsto aluminum cable or aluminum cable, steel reinforced (ACSR).

Aluminum cable, steel reinforced (ACSR) is used extensively for currentdistribution in rural electrification. Because the aluminum is extremelymalleable, it is readily damaged when a clamp is used to take taps fromthe ACSR line. Since the spans in rural electrification are quite long,vibration of the conductor has a tendency to cause it to fail at suchpoints of damage or at points of support. As a result it is generalpractice to protect the ACSR conductor at points of support with armorrods. These are, simply a group of short aluminum wires, about 3 or 4feet long, which are clamped about the circumference of the ACSRconductor. At the center of these wires the conductor is supported bythe suspension clamp and taps from the .ACSR, are made by clamping theconnector over the armor rods. The instant type of electrical connectoris especially suitable for clamping tap conductors to the armor rodswhich protect the ACSR conductor.

The principal objectof my invention is to provide a clamp which can bequickly and easily installed even on pole tops or other inconvenientlocations where linemen must work.

Another object of my invention is to provide a connector which has allits parts held together in assembled relationship even when open toreceive the conductors. In this manner, loose parts which may drop or belost are eliminated.

Another object of my invention is to provide a low cost assembly.

Still another object of my invention is to provide a means formaintaining constant pressure on the conductors even though theconductors may flow or creep under the applied pressure.

Another object of my invention is to :provide means for inhibiting orretarding the galvanic corrosion which may result from contact betweenaluminum and copper conductors in outdoor atmospheres.

A further object of my invention is to avoid a complete magnetic circuitabout the conductors which might bea result of making all parts offerrous materials.

I accomplish these and other objects and obtain my new results as willbe apparent from the device described in the following specification,particularly pointed out in the attached claim, and illustrated in theaccompanying drawing, in which:

Fig. 1 is a sideelevation of my preferred form of clamp.

Fig. 2 is abottom elevation of the same.

Fig. 3- is a side elevation, partially in section illustrating theunitary assembly.

Fig. 4-is a partial view of one end of the spring plate.

Referring more particularly to the drawing, reference numeral l0designates a cap plate, preferably made of iron for economy, andgalvanized thereafter. It is provided with a central transverse groove Il, for engaging an armor rod I2, and end tapped holes 14 and I3 oneither side of the groove.

The central plate 20, preferably made of copper alloyand galvanized, issimilarly provided with a corresponding groove 2|, with a groove 22, onthe opposite side thereof, for the copper conductor 23, and two endapertures 24 and 25. On the springy-plate 30, the third element,preferably made of phosphor bronze, is a cable groove 3| for theopposite side of the conductor 23, and 'end'holes 32 and 33, forentrance of two bolts 40 and 50' preferably made of galvanized steel,and provided with rolled threads 4| and 5! respectively.

In orderto prevent the parts from becoming separated when the'clamp isopened for insertion. of the conductors, bolt 50 is preferably threadedthrough'the cap l0 and the end of the screw is peened over as at 52 toprevent itswithdrawal. The threaded portion 4| of the other bolt 40v ispassed through the hole 32 in the spring plate 30 and the hole'in theplate is then reduced in diameter as indicated in Fig. 4 so as to permitthe shank of the screw 40 to slide freely therein, but to such an extentthat the threaded portion of the bolt cannot drop through the hole. Thisis true because the shank of a rolled thread screw is slightly smallerin diameter than the major diameter of the threads.

When the connector is to be installed, the bolt 50 which has the endpeened over is withdrawn as far as it will go. The other bolt 40 is thenunthreaded entirely and it will drop down until the threads encounterthe edge of the hole 32 in the spring plate 30. This will leave anopening in the side of the connector through which the armor rods overthe ACSR can pass. The free end of plate 20 can then be lifted forlateral entrance of conductor 23, if necessary.

The most popular sizes of ACSR are #2 and #4. In order to make my clampuniversal, I have designed a single size to accommodate both theseconductors over the armor rods. This means that the threaded portion ofthe bolts must be longer in order to clamp the small as well as thelarge size. But because the threaded portion of the bolts are longer,the bolt 40 which drops down to provide the open side will extendhigher, and will normally prevent the clamp from being installed on acontinuous conductor. In order to provide enough-room for properclearance, the peened bolt should be increased in length so that it canbe withdrawn the necessary additional amount. I have found that thepeened bolt 50 should be at least one-eighth inch longer than the otherbolt.

Where aluminum and copper conductors are connected outdoors, someprovision must be made to retard the galvanic corrosion which attach thealuminum. The aluminum and copper form a galvanic battery in thepresence of an electrolyte, which may be set up by moisture or by acorrosive atmosphere A small local current is set up with the aluminumacting as the anode and gradually being corroded away. By inserting theseparator 28 consisting of a galvanized copper alloy plate between theconductors, this action is retarded. The zinc is close to aluminum inthe electrochemical series and the groove 22 in which the copper wirerests is ground free of galvanizing permitting the copper wire to comein contact with the copper surface of the separator. Thus the solutionpotential between the copper and aluminum is cut down into smaller stepsexisting between aluminum and zinc, and between zinc and copper and,therefore, the galvanic corrosion rate is slowed down.

In order to avoid a complete magnetic circuit about the conductors, withresultant hysteresis losses and heating, I make my connector with partsso arranged that there is never a full ring of ferrous parts about theconductors. Even when both conductors tobe joined are aluminum. Iprovide at least one part, such as one screw, made of non-magneticmaterial. This prevents serious heating of the clamp which in turn mayprove very harmful to the conductors.

I have thus described my invention, but I desire it understood that itis not confined to the particular forms or uses shown and described, thesame being'merely illustrative, and that the invention may be carriedout in other ways without departing from the spirit of my invention,and, therefore, I claim broadly the right to employ all equivalentinstrumentalities coming within the scope of the appended claim,

and by means of which, objects of my invention are attained and newresults accomplished, as it is obvious that the particular embodimentsherein shown and described are only some of the many that can beemployed to attain these objects and accomplish these results.

What I claim and desire to secure by Letters Patent is as follows:

An electric connector for joining a tap conductor to a continuous maincable, comprising a cap plate having a transverse groove formed in thebottom face of its intermediate portion, the end portions of said capplate being formed with threaded openings, a central plate having atransverse groove formed in the upper face of its intermediate portioncomplemental to the transverse groove formed in the bottom face of thecap plate, said grooves coacting to receive and hold therebetween themain cable, said central plate being formed with an additionaltransverse groove in the bottom face of its intermediate portion, theend portions of the central plate having bolt receiving openingsextending therethrough, a bottom spring plate having a transverse grooveformed in the upper face of its intermediate portion complemental to thetransverse groove formed in the bottom face of the central plate toreceive and hold therebetween a tap conductor, said bottom plate beingformed with bolt receiving openings inthe end portions thereof, andbolts extending through the respective registering openings in theplates, the heads of the bolts adapted to engage the bottom plate andthe threaded ends of said bolts being threaded through the threadedopenings in the cap plate for maintaining the plates in clampedengagement with the main cable and tap conductor, one bolt being longerthan the other, the upper end of the longer bolt being peened over toprevent disengagement of said longer bolt from the cap plate, theshorter bolt being capable of withdrawal from the cap plate to permitentrance of the main cable between the cap and central plates, theopening in the bottom plate through which the shorter bolt passes beingsmaller than the diameter of the threaded portion of the shorter bolt toprevent the threaded end of said shorter bolt from drop-' ping throughthe hole provided therefor in the bottom plate, yet permit the slidingmovement of the unthreaded portion of the shank of the shorter bolttherethrough.

JULIAN RQGOFF.

